The invention relates to apparatus for preparing samples for analysis, for example for analysis by chromatography.
1. Field of the Invention
Document EP-0 180 511-B1 discloses an apparatus of this type, comprising a baseplate, a set of columns running across the upper part of the baseplate and each receiving an agent in powder form, and a set of tubes spread out in a carriage, toward the lower part of the baseplate. The carriage can move in sliding between a position of coincidence in which an aperture at the bottom of the columns is opposite an aperture at the top of the tubes so that liquid can be transferred from the columns into the tubes, and a laterally offset position in which the columns are placed over a basin borne by the carriage and able to receive the content of the columns. The apparatus comprises a mobile injection needle designed to inject various liquids into the aperture at the top of the columns that they pass through the agent in powder form and are collected in the tubes. An apparatus of this kind makes it possible, starting from raw samples, to prepare in the tubes, in an automated fashion, a great many samples designed for subsequent analysis by chromatography, or any other kind of analysis, such as mass spectrography and radioimmunoassay.
2. Background of the Invention
However, a drawback of this apparatus is that when the columns and tubes are in the position of coincidence, there is a risk that the liquid transferred from each column will splash toward the tubes adjacent to the tube associated with the column in question. There is therefore a risk of these adjacent tubes becoming contaminated. Such a risk reduces the reliability of the subsequent analysis of the samples. This drawback is particularly keenly felt when the aperture at the bottom of the columns consists of a small nozzle and the liquid is driven through the nozzle under pressure. In such an instance, the risk of splashing toward the adjacent tubes is very high.
There is therefore a desire to have an apparatus which exhibits the same advantages but in which the risk of cross-contamination of samples is considerably reduced.
Document U.S. Pat. No. 5,260,028 discloses an apparatus for solid-phase extraction, comprising a motor for driving the horizontal movement of the tubes with respect to cassettes along horizontal slideways, and another motor for driving the tubes in a vertical movement with respect to the cassettes along vertical slideways with a view to coupling them so that liquid can be transferred from one to the other without splashing. However, this apparatus is of a complicated and bulky structure.
One purpose of the invention is to provide an apparatus of a different type, and which in particular is of simpler and less bulky design.